Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint, idempotentHint, non-destructive, and closed-world, so the safety profile is fully covered elsewhere. The description adds nothing beyond that — no note on error behavior for missing ids, visibility/permission scoping, or what a budget record contains.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

A single short sentence with the key information front-loaded and no filler. It is efficient, though extremely terse even for a simple read tool.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a single-record read with rich annotations and a fully documented one-parameter schema, little more is needed. Missing only minor context such as not-found behavior, which is low-stakes here.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Only one parameter with 100% schema description coverage, so the schema fully documents the id. The description's 'by id' merely restates it and adds no format or validation detail; baseline 3 applies when the schema does the work.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb (read) and resource (expense_budget) plus the lookup key (id). Among many expense_* siblings it is distinguishable by name and by 'one ... by id', though the description itself doesn't explicitly contrast with expense_budget_list or expense_budget_update.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

No guidance on when to use this versus expense_budget_list, expense_aggregate, or expense_read. The only implicit cue is 'one ... by id', leaving the agent to infer that this is the single-record lookup path.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.